- #1
sineontheline
- 18
- 0
So I'm pretty sure I understand the formalism of dual vector spaces. (E.g. there exist objects that operate on vectors and take them to scalars. these objects themselves form a linear vector space).
But I'm having difficulty understanding where this comes from intuitively. How would I know that I need them if I'm trying to reason things out?
More clearly:
1) I have a linear vector space (LVS).
2) I say "I have addition of vectors from condition of LVS. From my experience with the outside world, I know I need my space of vectors to have notions of length and distance, not just rules for combining them."
3) Ok, then I need a way to combine vectors in my space that have something to do with how they're positionally related to one another.
4) ?
Now what?
1) How do I know that the distance operation I'm looking for is the scalar product?
2) Why do I need a notion of distance to specify a scalar product? (vuwngun => in order to have my scalar product to work, I need gun)
3) Why do I not need a notion of distance if I use objects from the dual space?
(wngun = wu => vuwu = scalar)
This might need to be in the GR forum, but I was reading the first chapter of Shankar for the billionth time when I was able to finally articulate all this. as you might be able to tell -- this is *really* bothering me, I'm really confused about the motivation for defining all this stuff. please hellllllp! <3
But I'm having difficulty understanding where this comes from intuitively. How would I know that I need them if I'm trying to reason things out?
More clearly:
1) I have a linear vector space (LVS).
2) I say "I have addition of vectors from condition of LVS. From my experience with the outside world, I know I need my space of vectors to have notions of length and distance, not just rules for combining them."
3) Ok, then I need a way to combine vectors in my space that have something to do with how they're positionally related to one another.
4) ?
Now what?
1) How do I know that the distance operation I'm looking for is the scalar product?
2) Why do I need a notion of distance to specify a scalar product? (vuwngun => in order to have my scalar product to work, I need gun)
3) Why do I not need a notion of distance if I use objects from the dual space?
(wngun = wu => vuwu = scalar)
This might need to be in the GR forum, but I was reading the first chapter of Shankar for the billionth time when I was able to finally articulate all this. as you might be able to tell -- this is *really* bothering me, I'm really confused about the motivation for defining all this stuff. please hellllllp! <3